In general, plastic films so strongly tend to be statically charged that their use may be greatly restricted in many instances. For example, in the case of light-sensitive silver halide photographic materials, supports made of polyethylene terephthalate are commonly used, which tend to be statically charged particularly under conditions of low humidity as in the winter. In instances in which high-speed photographic emulsions are coated at a high speed as in nowadays, it is particularly important to take a countermeasure for antistatic.
Once a light-sensitive material has been statically charged, static marks may occur because of release of the stored energy, or foreign matter such as dust may be attracted. This may cause occurrence of pinholes, resulting in a serious deterioration of product quality, and an attempt for its restoration brings about a great lowering of workability. For this reason, antistatic agents are commonly used in light-sensitive materials. Nowadays, cationic surface active agents, amphoteric surface active agents, surface active agents or polymeric compounds having a polyethylene oxide group, polymers having a sulfonic acid or phosphoric acid group in the molecule, etc. are used.
In such conventional techniques, however, antistatic properties may be greatly deteriorated when photographic processing is carried out. This is presumed to be due to a loss of antistatic properties as a result of the processing carried out through the steps such as developing using an alkali, fixing in an acidic environment, and washing. Hence, problems may arise such that pinholes are produced because of adhesion of dust in such an instance in which a film having been processed is further brought to printing as in the case of printing light-sensitive materials. Taking account of such problems, Japanese Patent Publications Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication (s)) No. 84658/1980 and No. 174542/1986 propose to provide an antistatic layer comprising i) a water-soluble conductive polymer having a carboxyl group, ii) a hydrophobic polymer having a carboxyl group and iii) a polyfunctional aziridine. This method makes it possible to retain antistatic properties even after the processing. This method, however, has a disadvantage when applied in an automatic transport apparatus comprising a transport path having a surface coated with Teflon, as is seen in a certain kind of scanners, where providing such an antistatic layer causes accumulation of static charges on the surface coated with Teflon, during the transport of light-sensitive materials, to cause faulty transport, i.e., wrong transport and output of light-sensitive materials. The method also has a disadvantage that providing such an antistatic layer tends to cause flaws after raw stock.